I have a 87 S-10 pickup with a tuned port 350 in it and I am not sure what kind of a cam you can run with this setup. It is a speed density setup so I think that limits the cam to a fairly mild one. I am used to building fords and we get away with running duration 230-240 all the time with a mass air setup. Should I convert this over to a mass air computer and harness or would I be waisting my time. I have a roller cam I got for another project that never got finished that is 230* in. 236* ex. .510 in .520 ex. I am pretty sure this is too large for speed density. Also is this TPI intake any good? Is there any way to make it better? I have been looking at the Holley Stealth Ram intake, anyone have any experience with this intake.

 

I have the Stealth Ram, and it kicks ***. I have SD as well and didn't know there were any limits to cam size as far as tuning goes, maybe alvin@pcm4less or one of the other professional prom burners could answer your question. I'd also like to know, I plan on doing either a 224/230 or 230/236 cam myself.

 

The reason SD is limited on cam size is because it uses the map sensor more than a mass air flow system does. If you have a monster cam that only makes 9 inches of vacuum at idle the computer thinks that there is a load on the motor and adds a crap load of fuel. Mass air systems know how much air is coming in so it knows not to add fuel at idle. At least thats how we deal with our mustangs anyways. A mass air mustang does not even have a MAP sensor.

 

That cam you just listed has 11.5" of vacuum at 1000rpms according to comp cams. Maybe it'll be ok then.

 

http://www.compcams.com/Technical/Dy...2HR-10_001.asp

 

no matter what cam you install you will need a CUSTOM prom for it performance resources does mine from small cams like 495/510 220/230 112* up to 570/586 238/248 110*of course with supporting mods!the first cam i mentioned is an old slp grind it ran real good in my 92z,12.70@107.
i am in the process of finishimg my other s10,just got repainted,tbi 350/700 mild drop is in mind,its really a work truck but you know how it is...

 

I found a whole website dedicated to SD:

http://www.speeddensity.org/

Doesn't look too populated though.

 

A good running stock engine will make anywhere from 16"-19" depending on elevation. 11.5 is still really low for a speed density car to try and idle.

 

I heard 11.5" is the minimum amount to operate all your accessories ok. I've been looking at several cams and want the biggest one that won't affect my braking. What would the minimum amount of vacuum for a SD system to operate properly be?

 

If you're talking about a stock chip you better have 15+" of vacuum.

If you're making your own custom chip, you can get away with less than 10"

 

Agreed. Stock chips need to see 15" at the very lowest or it will run pig rich sitting there at idle if it will even idle.

 

It's not the cam size that causes problems with tuning, but total overlap. My old 242-254 110 lsa cam in my maf car was hard to tune because of the overlap, and a sd car would be just as difficult. Reversion doesn't help any either. My vacuum at idle was like 7-8" and the power brakes were hard even with a vaccum canister and 10.5:1 compression. That cam needed at least 12:1 compression to run correctly.

Big cams aren't the problem with maf or sd ecm's, the real problem is trying to tune the ecm when the ecm is used to reading the O2 sensor for idle and part-throttle tuning. The big overlap cams throw a false reading at the O2 sensor so you can only get close at best without a wideband and lots of trial and error tuning. I never got rid of the part-throttle bucking in overdrive with that cam because of the overlap.

Don't be afraid of the bigger cams, just be prepared to spend alot more money on tuning, headaches, problems and complications if you pick one.

 

He would know

 

Finding somewhere that can tune these cars is near impossible where I live...........sigh.........